The present invention relates generally to printed circuit boards and in particular to a method and apparatus for splicing segments of flexible circuit boards when servicing or replacing electronic components in automobiles.
Automobiles include many complex electrical assemblies for use in sophisticated engine control systems including a variety of sensors for detecting such conditions as engine temperature, throttle position, engine speed and air intake. These control systems typically include microprocessors to process the signals from these sensors and produce control signals for operating engine components such as throttle valves, ignition coils and fuel injectors.
Ordinarily, the electronics in such control systems are interconnected via a printed circuit board. Printed circuit boards are used because they provide reliable connection between the electronic components. Typical circuit boards have a rigid substrate on which the circuit is printed. Due to their rigid construction, the electronics on the circuit board must be connected to sensors and vehicle components by a wiring harness. Wiring harnesses are costly and are prone to failure in the connection of the harness to the circuit board but also in the connection to connector pins. Moreover, wiring harnesses clutter the engine compartment making it more difficult to assemble and service the engine.
One method of providing reliable connections without using bulky and expensive wiring harnesses is to use flexible circuit boards typically made of a conductive layer laminated to a flexible insulating substrate. Such flexible circuit boards can be fabricated to include finger-like extensions that are sufficiently flexible to follow a curved path between the control circuitry and the sensor or vehicle component.
Such flexible circuit boards provide the advantage of obviating wire harnesses. Moreover, using such circuit boards can also eliminate pin connectors between the circuit board and the sensors or vehicle components, which can decrease cost as well as connection related problems. However, like wires, the finger-like extensions can be damaged from flexure and abrasion occurring during normal use of the automobile. And, without connectors between the circuit board and the sensors or components, it is ordinarily more difficult and expensive to service or replace components of the electrical assembly. This is because the remote components are directly connected to a main circuit board by the integral extensions. Thus, replacing one sensor or vehicle component ordinarily requires that the entire assembly to which it is connected be replaced.